1. Field of the Invention
This invention relates to cement mixing, and, more particularly, to mixing ingredients for cementitious products in which ingredients are measured by weight and by volume in one container, and where the ingredients in a second container are measured by weight.
2. Description of the Prior Art
For lightweight concrete products, cement and filler material are mixed, along with water, and other agents. In addition, previously hydrated cement and filler materials, previously mixed, may also be mixed with newly added filler material before being combined with water and cement for final mixing before being cast into molds.
The measuring of the various ingredients, prior to the final mixing, is, in the prior art, very cumbersome and labor intensive. The materials are generally measured either by weight or by volume, and then the various materials are combined for ultimate mixing, To have to weigh some of the ingredients and to measure by volume some of the other ingredients, and the separate handling steps in the separate measurement steps, can take an appreciable amount of time and manpower to accomplish. This is so particularly using previously mixed materials which consist of an unknown value of hydrated cement and fillers which have to be separated before measuring. Fillers are added by volume while hydrated cement must be added by its weight.
The apparatus of the present invention overcomes the deficiencies of the prior art by providing two different chambers into which ingredients are placed before being transferred from the two hoppers into a central mixing chamber. In one hopper, filler material contained in hydrated cement and fresh filler material is measured by volume and the hydrated cement is measured by weight. The measuring and weighing steps are automatically accomplished by the apparatus of the present invention. In the second hopper, water and cement are measured by weight, and the water and cement are mixed before being transferred to the central mixing chamber.